Mobile device, such as smart phone, has become indispensable to modern people in their everyday life. The smart phone provides many reminder functions and is virtually a small-sized computer. For example, the smart phone has the function of alarm reminder, and will remind the user when receiving a text message. These reminder functions provide convenience of use to the user. As the smart phone is capable of providing more and more new functions, how to provide more suitable functions for improving the user's experience of use has become a prominent task for the industries.